Polyetherimide resins with very low levels of residual contamination

ABSTRACT

Compositions and methods for producing compositions comprising a monoamine-endcapped polyimide component. Based on a gas chromatography mass spectroscopy analysis of a surface rinse of the composition performed at room temperature, the composition can have at least one surface with less than or equal to 5 ppb releasable phosphorous residuals, and less than or equal to 5 ppb releasable volatile organic compound residuals. The composition can also comprise less than or equal to 10 ppb combined releasable residuals. Because of the very low levels of residual contamination, the compositions can be used to produce a variety of articles including a disk drive.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to polymer compositions with very lowlevels of residual contamination, and more specifically to compositionscomprising a monoamine-endcapped polyimide component with very lowlevels of residual contamination.

2. Description of the Related Art

Polyetherimides are a class of polymers that display excellent hightemperature performance and can be processed to make molded articles,fibers, films, foams etc. For example, polyimide resins such as ULTEM®resin grades 1000 or 1010 with a melt viscosity (MI) range of 0.8-1.1and 1.6-2.0, respectively, find wide use in applications where hightemperature performance and easy processability is required. However,these resins do not meet stringent cleanliness requirements that aredictated by newer, high end applications. High end applications ofpolyetherimides, such as in semiconductors or fibers, require the resinto have very low contamination levels, or the processability and/orproduct performance is adversely affected.

Common resin contaminants could be organic or inorganic in nature, Theorganic contaminants are mostly lower molecular weight species. One suchlow molecular weight species is phthalic anhydride m-phenylene diamineimide (PAMI), formed by the reaction of two moles of phthalic anhydridewhich is used as an end cap in the polymer reaction, and one mole ofm-phenylene diamine (mPD), which is one of the monomers. This moleculehas been found to ‘plate out’ on equipment parts during the moldingoperation. U.S. Pat. No. 6,919,422, which is hereby incorporated byreference in its entirety, provides details of a polyimide compositionthat solves the above plate out issue by replacing the PAMI end cap witha monoamine end cap, such as aniline. Thus, in the place of PAMI, alarger molecule is formed on the reaction of 2 moles of aniline with onemole of the dianhydride monomer. This molecule does not plate out to theextent that PAMI does. A common inorganic contaminant is stabilizerIrgafos 168 and its oxidized version. The stabilizer is added to thepolymer prior to extrusion to lower color of the final resin. There isresidual stabilizer in measurable quantity in the resin pellets postextrusion. The residual stabilizer is linked to higher particle countsin the resin.

BRIEF SUMMARY OF THE INVENTION

A first embodiment relates to a composition comprising amonoamine-endcapped polyimide component. The monoamine-endcappedcomponent can be selected from the group consisting ofmonoamine-endcapped polyetherimides, monoamine-endcapped polyetherimidesulfones, and combinations thereof. Based on a gas chromatography massspectroscopy analysis of a surface rinse of the composition performed atroom temperature, the composition can have at least one surface withless than or equal to 5 ppb releasable phosphorous residuals, and lessthan or equal to 5 ppb releasable volatile organic compound residuals.The composition can also comprise less than or equal to 10 ppb combinedreleasable residuals.

A second embodiment relates to a process of melt-spinning fibers, theprocess comprising melting the composition of the first embodiment toform a melt, passing the melt through a spinnerette to form fibers, andstretching the fibers.

A third embodiment relates to a composition comprising: (a) from 60 to99 weight percent of a polyimide component selected from the groupconsisting of polyetherimides, polyetherimide sulfones, and combinationsthereof, wherein the composition contains <5 ppb releasable phosphorousresiduals, wherein the polyimide component is monoamine-endcapped; and(b) from 1 to 40 weight percent of a filler.

A fourth embodiment relates to a disk drive comprising: a disk; and anarticle enclosing at least one surface of the disk. The article cancomprise a polyimide component selected from the group consisting ofpolyetherimides, polyetherimide sulfones, and combinations thereof. Thecomposition can contain <5 ppb releasable phosphorous residuals. Thepolyimide component can be monoamine-endcapped.

A fifth embodiment relates to a disk drive comprising: a disk, a diskenclosure enclosing at least one surface of the disk, and a headactuated over the disk. The disk enclosure can comprise a polyimidecomponent selected from the group consisting of polyetherimides,polyetherimide sulfones, and combinations thereof. The polyimidecomponent can contain <5 ppb releasable phosphorous residuals. Thepolyimide component can be monoamine-endcapped. The head actuated overthe disk can comprise a read element, a write element, a preamp, and aninterconnect. The interconnect can comprise a first transmission line, asecond transmission line coupling the head to the preamp, and acompensation network operable to compensate for an impedancediscontinuity in the first and second transmission lines. Thecompensation network can comprise a first trace, and a second traceconnected in parallel with the first and second transmission lines. Ashape of the first and second traces can vary to form at least a firstcapacitor.

A sixth embodiment relates to a method for producing a polyimidecomponent selected from the group consisting of polyetherimides,polyetherimide sulfones, and combinations thereof. The polyimidecomponent can contain <5 ppb releasable phosphorous residuals. Thecomposition can comprise <10 ppb combined releasable contaminants. Themethod can comprise monoamine-endcapping the polyimide component.

DETAILED DESCRIPTION OF THE INVENTION

The invention is based on the remarkable discovery that it is nowpossible to make articles from polyetherimides and polyetherimidesulfones that have low amounts of releasable phosphorous residuals andlow amounts releasable volatile organic compound residuals.Advantageously, the relatively low amount of releasable phosphorousresiduals and releasable volatile organic compound makes ourcompositions and articles suitable for many electronic applicationsrequiring polymers that are clean-such as hard disk drive applications.

The present invention may be understood more readily by reference to thefollowing detailed description of preferred embodiments of the inventionas well as to the examples included therein.

All numeric values are herein assumed to be modified by the term“about,” whether or not explicitly indicated. The term “about” generallyrefers to a range of numbers that one of skill in the art would considerequivalent to the recited value (i.e., having the same function orresult). In many instances, the term “about” may include numbers thatare rounded to the nearest significant figure.

The present invention relates to polymer resins with very low levels ofresidual contamination. These polymers are suitable for applicationsthat have extremely stringent cleanliness requirements. These resins canbe articles of, but not limited to, data storage disk drives, fibers,membranes, parts used in the semi-conductor industry etc. to name a fewapplications.

The term “clean room ready,” as used in this application, means that ourcomposition (or an article made with our composition) has at least onesurface that releases less than or equal to 5 ppb phosphorous residuals,less than or equal to 5 ppb volatile organic compound residuals, suchthat the composition as a whole contained less than or equal to 10 ppbreleased residuals when the surface is exposed to conditions of use,e.g. based on a gas chromatography mass spectroscopy analysis of asurface rinse of the composition performed at room temperature.

Various embodiments relate to a monoamine-endcapped polyimide component.The polyimide can be selected from polyetherimides,siloxane-polyetherimides, polyetherimide sulfones, and combinationsthereof. The polyetherimides are of formula (1):

wherein a is more than 1, for example 10 to 1,000 or more, or morepreferably 10 to 500.

The group V in formula (1) is a tetravalent linker containing an ethergroup (a “polyetherimide” as used herein) or a combination of an ethergroups and arylene sulfone groups (a “polyetherimide sulfone”). Suchlinkers include but are not limited to: (a) substituted orunsubstituted, saturated, unsaturated or aromatic monocyclic andpolycyclic groups having 5 to 50 carbon atoms, optionally substitutedwith ether groups, arylene sulfone groups, or a combination of ethergroups and arylene sulfone groups; and (b) substituted or unsubstituted,linear or branched, saturated or unsaturated alkyl groups having 1 to 30carbon atoms and optionally substituted with ether groups or acombination of ether groups, arylene sulfone groups, and arylene sulfonegroups; or combinations comprising at least one of the foregoing.Suitable additional substitutions include, but are not limited to,ethers, amides, esters, and combinations comprising at least one of theforegoing.

The R group in formula (1) includes but is not limited to substituted orunsubstituted divalent organic groups such as: (a) aromatic hydrocarbongroups having 6 to 20 carbon atoms and halogenated derivatives thereof;(b) straight or branched chain alkylene groups having 2 to 20 carbonatoms; (c) cycloalkylene groups having 3 to 20 carbon atoms, or (d)divalent groups of formula (2):

wherein Q¹ includes but is not limited to a divalent moiety such as —O—,—S—, —C(O)—, —SO₂—, —SO—, —C_(y)H_(2y)— (y being an integer from 1 to5), and halogenated derivatives thereof, including perfluoroalkylenegroups.

In an embodiment, linkers V include but are not limited to tetravalentaromatic groups of formula (3):

wherein W is a divalent moiety including —O—, —SO₂—, or a group of theformula —O—Z—O— wherein the divalent bonds of the —O— or the —O—Z—O—group are in the 3,3′, 3,4′, 4,3′, or the 4,4′ positions, and wherein Zincludes, but is not limited, to divalent groups of formulas (4):

wherein Q includes, but is not limited to a divalent moiety including—O—, —S—, —C(O)—, —SO₂—, —SO—, —C_(y)H_(2y)— (y being an integer from 1to 5), and halogenated derivatives thereof, including perfluoroalkylenegroups.

In a specific embodiment, the polyetherimide comprise more than 1,specifically 10 to 1,000, or more specifically, 10 to 500 structuralunits, of formula (5):

wherein T is —O— or a group of the formula —O—Z—O— wherein the divalentbonds of the —O— or the —O—Z—O— group are in the 3,3′, 3,4′, 4,3′, orthe 4,4′ positions; Z is a divalent group of formula (3) as definedabove; and R is a divalent group of formula (2) as defined above.

In another specific embodiment, the polyetherimide sulfones arepolyimides comprising ether groups and sulfone groups wherein at least50 mole % of the linkers V and the groups R in formula (1) comprise adivalent arylene sulfone group. For example, all linkers V, but nogroups R, can contain an arylene sulfone group; or all groups R but nolinkers V can contain an arylene sulfone group; or an arylene sulfonecan be present in some fraction of the linkers V and R groups, providedthat the total mole fraction of V and R groups containing an arylsulfone group is greater than or equal to 50 mole %.

Even more specifically, polyetherimide sulfones can comprise more than1, specifically 10 to 1,000, or more specifically, 10 to 500 structuralunits of formula (6):

wherein Y is —O—, —SO₂—, or a group of the formula —O—Z—O— wherein thedivalent bonds of the —O—, SO₂—, or the —O—Z—O— group are in the 3,3′,3,4′, 4,3′, or the 4,4′ positions, wherein Z is a divalent group offormula (3) as defined above and R is a divalent group of formula (2) asdefined above, provided that greater than 50 mole % of the sum of molesY+moles R in formula (2) contain —SO₂— groups.

It is to be understood that the polyetherimides and polyetherimidesulfones can optionally comprise linkers V that do not contain ether orether and sulfone groups, for example linkers of formula (7):

Imide units containing such linkers are generally present in amountsranging from 0 to 10 mole % of the total number of units, specifically 0to 5 mole %. In one embodiment no additional linkers V are present inthe polyetherimides and polyetherimide sulfones.

In another specific embodiment, the polyetherimide comprises 10 to 500structural units of formula (5) and the polyetherimide sulfone contains10 to 500 structural units of formula (6).

The polyetherimide and polyetherimide sulfones can be prepared byvarious methods, including, but not limited to, the reaction of abis(phthalimide) for formula (8):

wherein R is as described above and X is a nitro group or a halogen.Bisphthalimides (8) can be formed, for example, by the condensation ofthe corresponding anhydride of formula (9);

wherein X is a nitro group or halogen, with an organic diamine of theformula (10):

H₂N—R—NH₂  (10),

wherein R is as described above.

Illustrative examples of amine compounds of formula (10) include:ethylenediamine, propylenediamine, trimethylenediamine,diethylenetriamine, triethylenetetramine, hexamethylenediamine,heptamethylenediamine, octamethylenediamine, nonamethylenediamine,decamethylenediamine, 1,12-dodecanediamine, 1,18-octadecanediamine,3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine,4-methylnonamethylenediamine, 5-methylnonamethylenediamine,2,5-dimethylhexamethylenediamine, 2,5-dimethylheptamethylenediamine,2,2-dimethylpropylenediamine, N-methyl-bis (3-aminopropyl) amine,3-methoxyhexamethylenediamine, 1,2-bis(3-aminopropoxy) ethane,bis(3-aminopropyl) sulfide, 1,4-cyclohexanediamine,bis-(4-aminocyclohexyl) methane, m-phenylenediamine, p-phenylenediamine,2,4-diaminotoluene, 2,6-diaminotoluene, m-xylylenediamine,p-xylylenediamine, 2-methyl-4,6-diethyl-1,3-phenylene-diamine,5-methyl-4,6-diethyl-1,3-phenylene-diamine, benzidine,3,3′-dimethylbenzidine, 3,3′-dimethoxybenzidine, 1,5-diaminonaphthalene,bis(4-aminophenyl) methane, bis(2-chloro-4-amino-3,5-diethylphenyl)methane, bis(4-aminophenyl) propane, 2,4-bis(b-amino-t-butyl) toluene,bis(p-b-amino-t-butylphenyl)ether, bis(p-b-methyl-o-aminophenyl)benzene, bis(p-b-methyl-o-aminopentyl) benzene,1,3-diamino-4-isopropylbenzene, bis(4-aminophenyl)ether and1,3-bis(3-aminopropyl) tetramethyldisiloxane. Mixtures of these aminescan be used. Illustrative examples of amine compounds of formula (10)containing sulfone groups include but are not limited to, diaminodiphenyl sulfone (DDS) and bis(aminophenoxy phenyl) sulfones (SAPS).Combinations comprising any of the foregoing amines can be used.

The polyetherimides can be synthesized by the reaction of thebis(phthalimide) (8) with an alkali metal salt of a dihydroxysubstituted aromatic hydrocarbon of the formula HO-V-OH wherein V is asdescribed above, in the presence or absence of phase transfer catalyst.Suitable phase transfer catalysts are disclosed in U.S. Pat. No.5,229,482. Specifically, the dihydroxy substituted aromatic hydrocarbonis a bisphenol, such as bisphenol A, or a combination of an alkali metalsalt of a bisphenol and an alkali metal salt of another dihydroxysubstituted aromatic hydrocarbon can be used.

In one embodiment, the polyetherimide comprises structural units offormula (5) wherein each R is independently p-phenylene or m-phenyleneor a mixture comprising at least one of the foregoing; and T is group ofthe formula —O—Z—O— wherein the divalent bonds of the —O—Z—O— group arein the 3,3′ positions, and Z is 2,2-diphenylenepropane group (abisphenol A group). Further, the polyetherimide sulfone comprisesstructural units of formula (6) wherein at least 50 mole % of the Rgroups are of formula (4) wherein Q is —SO₂— and the remaining R groupsare independently p-phenylene or m-phenylene or a combination comprisingat least one of the foregoing; and T is group of the formula —Z—O—wherein the divalent bonds of the —O—Z—O— group are in the 3,3′positions, and Z is a 2,2-diphenylenepropane group.

The polyetherimide and polyetherimide sulfone can be used alone or incombination. In one embodiment, only the polyetherimide is used. Inanother embodiment, the weight ratio of polyetherimide:polyetherimidesulfone can be from 99:1 to 50:50.

The polyimides can have a weight average molecular weight (Mw) of 5,000to 100,000 grams per mole (g/mole) as measured by gel permeationchromatography (GPC). In some embodiments the Mw can be 10,000 to80,000. The molecular weights as used herein refer to the absoluteaverage molecular weight (Mw).

The polyimides can have an intrinsic viscosity greater than or equal to0.2 deciliters per gram (dug) as measured in m-cresol at 25° C. Withinthis range the intrinsic viscosity can be 0.35 to 1.0 dl/g, as measuredin m-cresol at 25° C.

The polyimides can have a glass transition temperature of greater than180° C., specifically of 200° C. to 500° C., as measured usingdifferential scanning calorimetry (DSC) per ASTM test D3418. In someembodiments the polyimide, and in particular a polyetherimide, has aglass transition temperature of 240 to 350° C.

The polyimides can have a melt index of 0.1 to 10 grams per minute(g/min), as measured by American Society for Testing Materials (ASTM) DI238 at 340 to 370° C., using a 6.7 kilogram (kg) weight.

One process for the preparation of polyetherimides having structure (1)is referred to as the nitro-displacement process (X is nitro in formula(8)). In one example of the nitro-displacement process,N-methylphthalimide is nitrated with 99% nitric acid to yield a mixtureof N-methyl-4-nitrophthalimide (4-NPI) and N-methyl-3-nitrophthalimide(3-NPI). After purification, the mixture, containing approximately 95parts of 4-NPI and 5 parts of 3-NPI, is reacted in toluene with thedisodium salt of bisphenol-A (BPA) in the presence of a phase transfercatalyst. This reaction yields BPA-bisimide and NaNO₂ in what is knownas the nitro-displacement step. After purification, the BPA-bisimide isreacted with phthalic anhydride in an imide exchange reaction to affordBPA-dianhydride (BRADA), which in turn is reacted with meta-phenylenediamine (MPD) in ortho-dichlorobenzene in an imidization-polymerizationstep to afford the product polyetherimide.

An alternative chemical route to polyetherimides having structure (1) isa process referred to as the chloro-displacement process (X is Cl informula (8)). The chloro-displacement process is illustrated as follows:4-chlorophthalic anhydride and meta-phenylene diamine are reacted in thepresence of a catalytic amount of sodium phenyl phosphinate catalyst toproduce the bischlorophthalimide of meta-phenylene diamine (GAS No.148935-94-8). The bischlorophthalimide is then subjected topolymerization by chloro-displacement reaction with the disodium salt ofBRA in the presence of a catalyst in ortho-dichlorobenzene or anisolesolvent. Alternatively, mixtures of 3-chloro- and 4-chlorophthalicanhydride may be employed to provide a mixture of isomericbischlrophthalimides which may be polymerized by chloro-displacementwith BPA disodium salt as described above.

Siloxane polyetherimides can include polysiloxane/polyimide blockcopolymers having a siloxane content of greater than 0 and less than 40weight percent (wt %) based on the total weight of the block copolymer.The block copolymer comprises a siloxane block of Formula (1):

wherein R¹⁻⁶ are independently at each occurrence selected from thegroup consisting of substituted or unsubstituted, saturated,unsaturated, or aromatic monocyclic groups having 5 to 30 carbon atoms,substituted or unsubstituted, saturated, unsaturated, or aromaticpolycyclic groups having 5 to 30 carbon atoms, substituted orunsubstituted alkyl groups having 1 to 30 carbon atoms and substitutedor unsubstituted alkenyl groups having 2 to 30 carbon atoms, V is atetravalent linker selected from the group consisting of substituted orunsubstituted, saturated, unsaturated, or aromatic monocyclic andpolycyclic groups having 5 to 50 carbon atoms, substituted orunsubstituted alkyl groups having 1 to 30 carbon atoms, substituted orunsubstituted alkenyl groups having 2 to 30 carbon atoms andcombinations comprising at least one of the foregoing linkers, g equals1 to 30, and d is 2 to 20. Commercially available siloxanepolyetherimides can be obtained from SABIC Innovative Plastics under thebrand name SILTEM* (*Trademark of SABIC Innovative Plastics B.V.)

A first embodiment relates to a composition comprising amonoamine-endcapped polyimide component. The monoamine-endcappedpolyimide component can be aniline-endcapped. The monoamine-endcappedcomponent can be selected from the group consisting ofmonoamine-endcapped polyetherimides, monoamine-endcapped polyetherimidesulfones, and combinations thereof.

Based on a gas chromatography mass spectroscopy analysis of a surfacerinse of the composition performed at room temperature, the compositioncan have at least one surface with an amount of releasable phosphorousresiduals within a range having a lower limit and/or an upper limit. Therange can include or exclude the lower limit and/or the upper limit. Thelower limit and/or upper limit can be selected from 0.0.5, 1, 1.5, 2,2.5, 3, 3.5, 4, 4, 5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5,11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5,18, 18.5, 19, 19.5, and 20 ppb. For example, at least one surface of thecomposition can have 5 ppb releasable phosphorous residuals, <3 ppbphosphorous, or <1 ppb phosphorous.

Based on a gas chromatography mass spectroscopy analysis of a surfacerinse of the composition performed at room temperature, the compositioncan have at least one surface with an amount of releasable volatileorganic compound residuals within a range having a lower limit and/or anupper limit. The range can include or exclude the lower limit and/or theupper limit. The lower limit and/or upper limit can be selected from 0,0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9,9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16,16.5, 17, 17.5, 18, 18.5, 19, 19.5, and 20 ppb. For example, at leastone surface of the composition can have ≦5 ppb releasable volatileorganic compound residuals.

The composition can have an amount of combined releasable residualswithin a range having a lower limit and/or an upper limit. The range caninclude or exclude the lower limit and/or the upper limit. The lowerlimit and/or upper limit can be selected from 0, 0.5, 1, 1.5, 2, 2.5, 3,3.5, 4, 4, 5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11,11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18,18.5, 19, 19.5, and 20 ppb. For example, the composition can alsocomprise ≦10 ppb combined releasable residuals.

The composition according to the first embodiment can further comprise afiller selected from the group of organic fillers, inorganic fillers,and combinations thereof. The composition according to the firstembodiment can further comprise a filler selected from the group ofcarbon fibers, glass fibers, minerals, and combinations thereof.

The composition according to the first embodiment can further compriseone or more stabilizers in an amount within a range having a lower limitand/or an upper limit. The range can include or exclude the lower limitand/or the upper limit. The lower limit and/or upper limit can beselected from 0, 0.001, 0.002, 0.003, 0.004, 0.005, 0.01, 0.015, 0.02,0.025, 0.03, 0.035, 0.04, 0.045, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35,0.4, 0.45, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and 5 weight percentbased on the total weight of the composition. For example, thecomposition can contain <2 weight percent stabilizers, <1 weight percentstabilizers, <0.001 weight percent stabilizers, or no stabilizers.

The composition according to the first embodiment can be employed in anarticle. The article can be circular and can have a diameter within arange having a lower limit and/or an upper limit. The range can includeor exclude the lower limit and/or the upper limit. The lower limitand/or upper limit can be selected from 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5,5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, and 10 cm. For example, thearticle can be circular and can have a diameter ranging from 2 cm to 5cm. The article can have a thickness within a range having a lower limitand/or an upper limit. The range can include or exclude the lower limitand/or the upper limit. The lower limit and/or upper limit can beselected from 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2,1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6,6.5, 7, 7.5, 8, 8.5, 9, 9.5, and 10 mm. For example, the article canhave a thickness ranging from 0.5 mm to 2 mm.

Based on a gas chromatography mass spectroscopy analysis of vaporsreleased at 350 degrees Celsius, for 15 minutes, the compositionaccording to the first embodiment can have at least one surface can havean amount of combined releasable inorganic volatile compounds andorganic volatile compounds within a range having a lower limit and/or anupper limit. The range can include or exclude the lower limit and/or theupper limit. The lower limit and/or upper limit can be selected from1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500,7000, 7500, 8000, 8500, 9000, 9500, 10000, 10500, 11000, 11500, 12000,12500, 13000, 13500, 14000, 14500, 15000, 15500, 16000, 16500, 17000,17500, 18000, 18500, 19000, 19500, and 20000 ppb. For example, based ona gas chromatography mass spectroscopy analysis of vapors released at350 degrees Celsius, for 15 minutes, the composition according to thefirst embodiment can have at least one surface can have less than orequal to 20,000 ppb combined releasable inorganic volatile compounds andorganic volatile compounds.

A second embodiment relates to a process of melt-spinning fibers, theprocess comprising melting the composition of claim 1 to form a melt,passing the melt through a spinnerette to form fibers, and stretchingthe fibers. The fibers can exhibit reduced strand breakage.

A third embodiment relates to a composition comprising: (a) from 60 to99 weight percent of a polyimide component selected from the groupconsisting of polyetherimides, polyetherimide sulfones, and combinationsthereof, wherein the composition contains <5 ppb releasable phosphorousresiduals, wherein the polyimide component monoamine-endcapped; and (b)from 1 to 40 weight percent of a filler. The polyimide component can beaniline-endcapped. The filler can be selected from the group of organicfillers, inorganic fillers, and combinations thereof. The filler can beselected from the group of carbon fibers, fiber glass, minerals, andcombinations thereof.

A fourth embodiment relates to a disk drive comprising: a disk; and anarticle enclosing at least one surface of the disk. The article cancomprise a polyimide component selected from the group consisting ofpolyetherimides, polyetherimide sulfones, and combinations thereof. Thecomposition can contain <5 ppb releasable phosphorous residuals. Thepolyimide component can be monoamine-endcapped. The polyimide componentcan be aniline-endcapped.

A fifth embodiment relates to a disk drive comprising: a disk, a diskenclosure enclosing at least one surface of the disk, and a headactuated over the disk. The disk enclosure can comprise a polyimidecomponent selected from the group consisting of polyetherimides,polyetherimide sulfones, and combinations thereof. The polyimidecomponent can contain <5 ppb releasable phosphorous residuals. Thepolyimide component can be monoamine-endcapped. The head actuated overthe disk can comprise a read element, a write element, a preamp, and aninterconnect. The interconnect can comprise a first transmission line, asecond transmission line coupling the head to the preamp, and acompensation network operable to compensate for an impedancediscontinuity in the first and second transmission lines. Thecompensation network can comprise a first trace, and a second traceconnected in parallel with the first and second transmission lines. Ashape of the first and second traces can vary to form at least a firstcapacitor.

A sixth embodiment relates to a method for producing a polyimidecomponent selected from the group consisting of polyetherimides,polyetherimide sulfones, and combinations thereof. The polyimidecomponent can contain <5 ppb releasable phosphorous residuals. Thecomposition can comprise <10 ppb releasable contaminants. The method cancomprise monoamine-endcapping the polyimide component. Themonoamine-endcapping can be performed in the absence of phosphorous andvolatile organic compounds.

EXAMPLES

Four resin grades were tested side by side to compare contaminantlevels. The resin grades used for the comparison study were 1010standard (PA end cap, with stabilizer), 1010K (aniline end cap, withstabilizer), 1010 NS (PA end cap, no stabilizer), and 1010K NS (anilineend cap, no stabilizer). The first test involved extracting the surfacecontaminants from the resin using three common solvents—methanol,acetonitrile and hexane. The contaminants were identified and theirlevels determined using GC-MS. The same process of solvent extractionand analysis was done after baking the resin at 85 degrees Celsius and350 degrees Celsius in an oven for 15 minutes. The second test involvedGC-MS of volatiles outgassed from resin at 350 degrees Celcius.

Table 1 summarizes materials used in the Examples.

TABLE 1 Material Description Source PEI 1 Ultem ® 1010 Resin SABICInnovative Plastics PEI 2 Ulteme ® 1010 K Resin SABIC InnovativePlastics PEI 3 Stabilizer-Free Phthalic anhydride SABIC Innovativeendcapped-Polyetherimide Resin Plastics PEI 4 Aniline-end-cappedStabilizer Free SABIC Innovative Polyetherimide Resin Plastics

PEI 3 Preparation Process

The experimental material, labeled as PEI 3 above, was made according tothe following procedure. Synthesis of standard PEI with no phosphite orhindered phenol stabilizer added. Into a reaction vessel was charged552.7 kg 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydridehereinafter referred to as bisphenol-A dianhydride or “BPADA”(approximate composition, 97.6 mole % BPADA, 2.4 mole % mono N-methylimide of BPADA), 8.12 kg of phthalic anhydride (PA) and 1155 liters ofo-dichlorobenzene (ODCB). The reaction mixture was heated to 150-160° C.Molten m-phenylene diamine (MPD) (116.3 kg) at 140-150° C. was addedover the course of 30 minutes. After the MPD addition was complete, thereaction mixture was heated to 180° C. with removal of water. Once theimidization was essentially complete and no further water was evolved,the reaction mixture was moved to a hold tank kept at 170° C. and thenfed into a solvent removal system. Solvent was removed using a wipedfilm evaporator reducing ODCB down to less than 500 ppm. The moltenpolymer was extruded into strands, cooled in a water bath and chopped togive finished pellets. The resultant polymer had a Mw of about 31,200g/mole.

PEI 4 Preparation Process

The experimental material, labeled as PEI 4 above, was made according tothe following procedure. Synthesis of aniline end-capped PEI with nophosphite or hindered phenol stabilizer added. Into a reaction vesselwas charged 567 kg BPADA (approximate composition, 97.6 mole % BPADA,2.4 mole % mono N-methyl imide of BPADA) and 1155 liters ofo-dichlorobenzene (ODCB). The reaction mixture was heated to 150-160° C.Molten MPD (113.4 kg) at 140-150° C. was added over the course of 30minutes. Simultaneously, 5.1 kg aniline was added. Both the aniline andMPD were pumped through a static mixer while being added to the BPADA.After the MPD addition was complete, the reaction mixture was heated to180° C. with removal of water. The reaction mixture was moved to a holdtank kept at 170° C. and then fed into a solvent removal system. Solventwas removed using a wiped film evaporator reducing ODCB down to lessthan 500 ppm. The molten polymer was extruded into strands, cooled in awater bath and chopped to give finished pellets. The resultant polymerhad a Mw of about 31,200 g/mole.

Analytical Testing Procedure for Determining Clean Room Readiness

The analytical testing procedure for determining whether compositionswere clean room ready is described below. For the purposes of “Cleanroom ready” meant that our composition (or an article made with ourcomposition) had at least one surface that releases less than or equalto 5 ppb phosphorous residuals, less than or equal to 5 ppb volatileorganic compound residuals, such that the composition as a wholereleased less than or equal to 10 ppb residuals.

Four resin grades (PEI 1, PEI 2, PEI 3, and PEI 4) were tested side byside to compare contaminant levels. The resin grades used for thecomparison study were PEI (phthalic anhydride end capped polyetherimideresin, with stabilizer), PEI 2 (aniline end cap, with stabilizer) andPEI 3 (phthalic anhydride end cap, with no stabilizer), PEI 4 (anilineend cap, no stabilizer).

The first test involved extracting the surface contaminants from theresin using acetonitrile. The contaminants were identified and theirlevels determined using GC-MS. The second test consisted of thermaldesorption after baking the resin at 350° C. in an oven for 15 minutes.

Gas Chromatography-Mass Spectroscopy (GC-MS) Analysis of Surface Rinseof Composition:

GC-MS analysis was performed on an Agilent 5975 GC-MS instrument. ATR-5MS column (30M×0.25 mm ID×0.25μ film thickness) was used to separatethe analytes of interest. A 3 μl injection was performed using anautomatic liquid sampler. The injection port was held at 300° C. and asplitless injection was performed with a purge flow of 1.0 ml/min. Theoven was initially held at 35° C. for 1 min and then ramped at 15°C./min to 300° C. and held for 31.33 min. The mass spectrometer wasoperated in scan mode (33-700 amu). The results are summarized in Table2.

TABLE 2 Elution Time Identification Peak Area ng/g 13.99 internalstandard (D-10 anthracene, 7922513 N/A further described in Example 1)17.24 9-octadecenamide 1305986 8.2 19.44 13-docosenamide 345387 2.2 N/A:Not Applicable

Example 1 Inventive

The GC-MS analysis procedure above was practiced. More particularly, agram sample of PEI 4 was poured directly into a 40 ml scintillationvial. A 10 ml aliquot of acetonitrile (HRGC grade) was added to the vialby pipette. The vial was then capped and placed on a mechanical shakerfor 5 min. The wash solution was then separated from the pellets bypouring into a new, 40 ml scintillation vial. The scintillation vial wasthen placed under a nitrogen purge to evaporate the solvent to dryness.A 0.3 ml aliquot of acetonitrile was added to the wash residue andshaken for 15 min to redissolve the residue. The solution was thentransferred to a low volume reservoir vial and evaporated to drynessunder the nitrogen purge. A 50 ul solution of 2 ppm D-10 anthracene wasthen added to the low-volume reservoir vial and analyzed by GC-MS. N.D.is for “not detected.”

The results of Example 1 are summarized in Table 3. PEI 4 was found tobe the cleanest per the test protocol above and is expected to performbetter during processing and final part performance.

TABLE 3 Elution Time Identification Peak Area ng/g 13.99 internalstandard 6151522 16.17 Hexadecanamide 201395 1.6 17.24 9-octadecenamide303938 2.4 17.36 Octadecanamide 0 N.D. 18.1 di-octyl phthalate 0 N.D.19.44 13-docosenamide 0 N.D. 28.23 Hindered Phosphite 0 N.D. 33.49C20-C40 Organic Molecule 0 N.D.

The results of Example 1 show that our composition had at least onesurface releasing < or =5 ppb releasable phosphorous residuals, < or =5ppb releasable volatile organic compound residuals, and wherein thecomposition released < or =10 ppb releasable residuals was clean roomready.

More particularly, our results show that articles molded from the resinmaterial used above (a stabilizer-free aniline-capped polyetherimide)released detectable combined amount of 4.0 ppb, substantially below theamount of residuals obtained with comparative examples as furtherdescribed below.

Example 2 Comparative

A GC-MS analysis with acetonitrile (ACN) rinse of PEI 1 (Ultem® 1010Resin) was practiced. A 5 gram sample of PEI 1 was poured directly intoa 40 ml scintillation vial, A 10 ml aliquot of acetonitrile (HRGC grade)was added to the vial by pipette. The vial was then capped and placed ona mechanical shaker for 5 min. The wash solution was then separated fromthe pellets by pouring into a new, 40 ml scintillation vial. Thescintillation vial was then placed under a nitrogen purge to evaporatethe solvent to dryness. A 0.3 ml aliquot of acetonitrile was added tothe wash residue and shaken for 15 min to redissolve the residue. Thesolution was then transferred to a low volume reservoir vial andevaporated to dryness under the nitrogen purge. A 50 ul solution of 2ppm D-10 anthracene was then added to the low-volume reservoir vial andanalyzed by GC-MS. N.D. is for “not detected.” To measure the results,the procedures “Analytical Testing Procedure” and “GC MS Analysis”described above were practiced.

The results of Example 2 are summarized in Table 4.

TABLE 4 Elution Time Identification Peak Area ng/g 13.99 internalstandard 11892575 16.17 Hexadecanamide N.D. 17.24 9-octadecenamide1260016 5.2 17.36 Octadecanamide N.D. 18.1 di-octyl phthalate 197172 0.819.44 13-docosenamide 509232 2.1 28.2 Hindered Phosphite 3969834 16.4 33.5 C20-C40 Organic Molecule 2750055 11.3 

The results of Example 2 show that articles made from PEI 1 were foundto be contaminated per the test protocol above and is not expected toperform during processing and final part performance. Our results showthat the respective composition (which was not aniline-endcapped) wasnot clean room ready. More particularly, our results showed thatarticles molded from the resin material used above released detectablecombined amount of 35.8 ppb, substantially above the amount of residualsobtained with our invention.

Example 3 Comparative

A GC-MS analysis with acetonitrile (ACN) rinse of PEI 2 (ULTEM® PEI1010K) was practiced. A 5 gram sample of PEI 2 (ULTEM® PEI 1010K Resin)was poured directly into a 40 ml scintillation vial. A 10 ml aliquot ofacetonitrile (HRGC grade) was added to the vial by pipette. The vial wasthen capped and placed on a mechanical shaker for 5 min. The washsolution was then separated from the pellets by pouring into a new, 40ml scintillation vial. The scintillation vial was then placed under anitrogen purge to evaporate the solvent to dryness. A 0.3 ml aliquot ofacetonitrile was added to the wash residue and shaken for 15 min toredissolve the residue. The solution was then transferred to a lowvolume reservoir vial and evaporated to dryness under the nitrogenpurge. A 50 ul solution of 2 ppm D-10 anthracene was then added to thelow-volume reservoir vial and analyzed by GC-MS. N.D. is for “notdetected.” To measure the results, the procedures “Analytical TestingProcedure” and “GC MS Analysis” described above were practiced.

The results of Example 3 are summarized in Table 5. PEI 2 was found tobe contaminated per the test protocol above and is not expected toperform during processing and final part performance.

TABLE 5 Elution Time Identification Peak Area ng/g 13.99 internalstandard 9477817 16.17 Hexadecanamide N.D. 17.24 9-octadecenamide1942940 10.2  17.36 Octadecanamide 287835 1.5 18.1 di-octyl phthalate239276 1.3 19.44 13-docosenamide 829302 4.4 28.23 Hindered Phosphite4211276 22.1  33.5 C20-C40 Organic Molecule N.D.

The results of Example 3 show that articles made from PEI 2 were notclean room ready. More particularly, our results show that articlesmolded from the resin material used above released detectable combinedamount of 39.5 ppb, substantially above the amount of residuals obtainedwith our invention.

Example 4 Comparative

A GC-MS analysis with acetonitrile (ACN) rinse of PEI 3 was practiced. A5 gram sample of PEI 3 (the experimental polyetherimide sample describedabove) was poured directly into a 40 ml scintillation vial. A 10 mlaliquot of acetonitrile (HRGC grade) was added to the vial by pipette.The vial was then capped and placed on a mechanical shaker for 5 min.The wash solution was then separated from the pellets by pouring into anew, 40 ml scintillation vial. The scintillation vial was then placedunder a nitrogen purge to evaporate the solvent to dryness. A 0.3 mlaliquot of acetonitrile was added to the wash residue and shaken for 15min to redissolve the residue. The solution was then transferred to alow volume reservoir vial and evaporated to dryness under the nitrogenpurge. A 50 ul solution of 2 ppm D-10 anthracene was then added to thelow-volume reservoir vial and analyzed by GC-MS. N.D. is for “notdetected.” To measure the results, the procedures “Analytical TestingProcedure” and “GC MS Analysis” described above were practiced.

The results of Example 4 are summarized in Table 6. Resin EXUM0236 wasfound to be contaminated per the test protocol above and is not expectedto perform during processing and final part performance.

TABLE 6 Elution Time Identification Peak Area ng/g 13.99 internalstandard 11798309 16.17 Hexadecanamide N.D. 17.24 9-octadecenamide1234298 5.1 17.36 Octadecanamide 213926 0.9 18.1 di-octyl phthalate267399 1.1 19.44 13-docosenamide 580567 2.4 28.23 Hindered PhosphiteN.D. 33.49 C20-C40 Organic Molecule 2151969 8.9

Our results show that when a composition comprising a polyimidecomponent selected from the group consisting of polyetherimides,polyetherimide sulfones, and combinations thereof; wherein the polyimidecomponent is phosphorous-free, not aniline-endcapped and the compositionis not clean room ready. More particularly, our results show thatarticles molded from the resin material used above released detectablecombined amount of 18.4 ppb, substantially above the amount of residualsobtained with our invention.

Example 5 Inventive

The purpose of this example was to determine the releasable residuals ofarticles made from our aniline end-capped polyetherimide resin at highertemperatures than those conducted at room temperature (the temperatureat which gas chromatography mass spectroscopy analysis was practiced at350 for 15 minutes (also referred to as Thermal Desorption).

A Thermal Desorption GC-MS analysis of PEI 4 was practiced. A ˜100 mgsample of each set of PEI 4 was analyzed separately by thermaldesorption GC-MS. The samples were heated to either 350° C. for 15 minand desorbed compounds were cryogenically trapped (−120° C.). The trapwas then rapidly heated to 350° C. and evolved compounds were analyzedby GC-MS.

The results of Example 5 are summarized in Table 7. Resin PEI 4 wasfound to be the cleanest per the test protocol above and is expected toperform better during processing and final part performance.

TABLE 7 Elution Peak ng/g Time Identification Area (ppb) TimeIdentification Peak Area ng/g 10.49 Methylbenzofuran 1.08E+08 841 13.56tert-butylphenol N.D. 14.1 phthalic anhydride N.D. 14.92 unknown, MW =204 N.D. 15.04 unknown, MW = 188 N.D. 15.242,3-dihydro-3,3,5,6-tetramethyl 1H- N.D. Inden-1-one, MW = 188 16.05di-tert-butylphenol N.D. 16.39 unknown, MW = 206 1.10E+08 860 16.32di-tert-butylphenol isomer N.D. 18.75 MW = 210 1.78E+09 13896  22.342-phenyl-1H-Isoindole-1,3(2H)dione, 31206119 243 MW = 223 25.91 MW =238, mono-amine N.D. 26.48 unknown, MW = 293 22551323 176 28.85 unknown,MW = 315 36088586 281 30.29 unknown, MW = 380 18626867 145 30.95unknown, MW = 355 1.04E+08 811 31.22 Hindered Phosphite N.D.

The results of Example 5 show that articles made from our compositionwere clean room ready. The results also show that articles molded fromthe resin material used above released detectable combined amount of17253 ppb substantially below the amount of residuals obtained withComparative Example 6.

Example 6 Comparative

A Thermal Desorption GC-MS analysis of PEI 1 was practiced. A ˜100 mgsample of each set of ULTEM® PEI 1010 was analyzed separately by thermaldesorption GC-MS. The samples were heated to either 350° C. for 15 minand desorbed compounds were cryogenically trapped (−120° C.). The trapwas then rapidly heated to 350° C. and evolved compounds were analyzedby GC-MS.

The results of Example 6 are summarized in Table 8. Resin PEI 1 wasfound to be contaminated per the test protocol above and is not expectedto perform during processing and final part performance.

TABLE 8 Elution Time Identification Peak Area ng/g 10.49methylbenzofuran N.D. 13.56 tert-butylphenol 1.25E+08 970 14.1 phthalioanhydride 2.20E+08 1716  14.92 unknown, MW = 204 16091438 125 15.04unknown, MW = 188 27346159 213 15.24 2,3-dihydro-3,3,5,6-tetramethyl 1H-41131277 321 Inden-1-one, MW = 188 16.05 di-tert-butylphenol 1.65E+0912878  16.39 unknown, MW = 206 N.D. 16.32 di-tert-butylphenol isomer1.34E+09 10472  18.71 MW = 210 2.75E+08 2142  22.342-phenyl-1H-Isoindole-1,3(2H)dione, N.D. MW = 223 25.91 MW = 238,mono-amine 67511207 526 26.37 unknown, MW = 293 43221302 337 28.85unknown, MW = 315 N.D. 30.29 unknown, MW = 380 N.D. 30.95 unknown, MW =355 N.D. 31.22 Hindered Phosphite 5.25E+09 40900  32.2 HinderedPhosphite 1.58E+09 12306 

The results of Example 6 show that when a composition comprising apolyimide component selected from the group consisting ofpolyetherimides, polyetherimide sulfones, and combinations thereof;wherein the polyimide component is not phosphorous-free, notaniline-endcapped and the composition is not clean room ready. Theresults also show that articles molded from the resin material usedabove released detectable combined amount of 82906 ppb substantiallyabove the amount of residuals obtained with our invention.

Although the present invention has been described in considerable detailwith reference to certain preferred versions thereof, other versions arepossible. Therefore, the spirit and scope of the appended claims shouldnot be limited to the description of the preferred versions containedherein.

The reader's attention is directed to all papers and documents which arefiled concurrently with this specification and which are open to publicinspection with this specification, and the contents of all such papersand documents are incorporated herein by reference.

All the features disclosed in this specification (including anyaccompanying claims, abstract, and drawings) may be replaced byalternative features serving the same, equivalent or similar purpose,unless expressly stated otherwise. Thus, unless expressly statedotherwise, each feature disclosed is one example only of a genericseries of equivalent or similar features.

Any element in a claim that does not explicitly state “means for”performing a specified function, or “step for” performing a specificfunction, is not to be interpreted as a “means” or “step” clause asspecified in 35 U.S.C §112, sixth paragraph. In particular, the use of“step of” in the claims herein is not intended to invoke the provisionsof 35 U.S.C §112, sixth paragraph.

1-10. (canceled)
 11. An article comprising a monoamine-endcappedpolyimide component selected from the group consisting ofmonoamine-endcapped polyetherimides, monoamine-endcapped polyetherimidesulfones, and combinations thereof, wherein the composition, based on agas chromatography mass spectroscopy analysis of a surface rinse of thecomposition performed at room temperature, has at least one surface withless than or equal to 5 ppb releasable phosphorous residuals, less thanor equal to 5 ppb releasable volatile organic compound residuals, andwherein the composition comprises less than or equal to 10 ppb combinedreleasable residuals, wherein the article is circular and has a diameterranging from 2 cm to 5 cm.
 12. An article comprising amonoamine-endcapped polyimide component selected from the groupconsisting of monoamine-endcapped polyetherimides, monoamine-endcappedpolyetherimide sulfones, and combinations thereof, wherein thecomposition, based on a gas chromatography mass spectroscopy analysis ofa surface rinse of the composition performed at room temperature, has atleast one surface with less than or equal to 5 ppb releasablephosphorous residuals, less than or equal to 5 ppb releasable volatileorganic compound residuals, and wherein the composition comprises lessthan or equal to 10 ppb combined releasable residuals, wherein thearticle has a thickness ranging from 0.5 mm to 2 mm.
 13. (canceled) 14.A process of melt-spinning fibers, the process comprising, melting acomposition comprising a monoamine-endcapped polyimide componentselected from the group consisting of monoamine-endcappedpolyetherimides, monoamine-endcapped polyetherimide sulfones, andcombinations thereof, wherein the composition, based on a gaschromatography mass spectroscopy analysis of a surface rinse of thecomposition performed at room temperature, has at least one surface withless than or equal to 5 ppb releasable phosphorous residuals, less thanor equal to 5 ppb releasable volatile organic compound residuals, andwherein the composition comprises less than or equal to 10 ppb combinedreleasable residuals to form a melt, passing the melt through aspinnerette to form fibers, and stretching the fibers.
 15. The processof claim 14, wherein the fibers exhibit reduced strand breakage. 16-19.(canceled)
 20. A disk drive comprising: a disk; and an article enclosingat least one surface of the disk, wherein the article comprises apolyimide component selected from the group consisting ofpolyetherimides, polyetherimide sulfones, and combinations thereof,wherein the composition contains <5 ppb releasable phosphorous, andwherein the polyimide component is monoamine-endcapped.
 21. The diskdrive of claim 20, wherein the polyimide component ismonoamine-endcapped, wherein the polyimide component isaniline-endcapped.
 22. A disk drive comprising: (a) a disk; (b) a diskenclosure enclosing at least one surface of the disk, wherein the diskenclosure comprises a polyimide component selected from the groupconsisting of polyetherimides, polyetherimide sulfones, and combinationsthereof, wherein the polyimide component contains <5 ppb releasablephosphorous residuals, and wherein the polyimide component ismonoamine-endcapped; and (c) a head actuated over the disk, the headcomprising a read element, a write element, a preamp, and aninterconnect, the interconnect comprising a first transmission line, asecond transmission line coupling the head to the preamp, and acompensation network operable to compensate for an impedancediscontinuity in the first and second transmission lines, thecompensation network comprising a first trace, and a second traceconnected in parallel with the first and second transmission lines,wherein a shape of the first and second traces varies to form at least afirst capacitor.
 23. A method for producing a polyimide componentselected from the group consisting of polyetherimides, polyetherimidesulfones, and combinations thereof, wherein the polyimide componentcontains <5 ppb releasable phosphorous residuals, and wherein thecomposition comprises <10 ppb releasable contaminants, the methodcomprising monoamine-endcapping the polyimide.
 24. The method of claim23, wherein the monoamine-endcapping is done in the absence ofphosphorous and volatile organic compounds.